function  gundong(value){
    var  pos
    if  (document.documentElement  &&  document.documentElement.scrollTop)  {
        pos  =  document.documentElement.scrollTop;
    }  else  if  (document.body)  {
        pos  =  document.body.scrollTop;
    }
    window.scroll(0,pos+value);
}
function openOverlay(url){

    // if the function argument is given to overlay,
    // it is assumed to be the onBeforeLoad event listener
    var overlay = $("#overlay").overlay({

        mask: '#666',
        effect: 'apple',
        api:true
    });
    var wrap = overlay.getOverlay().find(".contentWrap");
    wrap.load(url);
    overlay.load();
}